Wednesday, August 14, 2013

In this post I want to talk about the thing that makes LaTeX so immensely powerful: it is programmable.

It is the great tragedy of modern computing that the industry has, for the most part, systematically trained people to be terrified of their computers. Things are changing all the time, usually in baffling ways, and those little changes all too often completely break other things we rely on. One consequence of this, though other issues compound the problem, is that most people have very powerful universal computing machines at their disposal but never write even a small program to solve a problem they might have.

This is not the place to teach computer programming, but I can introduce you to some very basic programming within LaTeX, to give you the power to radically alter the appearance of your conlanging documentation with just a few simple changes. It is this programmability of LaTeX that makes it such a powerful tool. Fortunately, most easy things are easy, so we'll start with that.

Text Appearance

Before we get to the programming, we'll start with the simple commands LaTeX uses to change basic font appearance. For example, from time to time we might want text to appear in italics or bold. In modern LaTeX, you just wrap the text you want to change in simple commands, \textit for italics and \textbf for bold. For example, \textbf{lorem ipsum dolor sit amet} will typeset that bit of gibberish in bold.

In addition to the bold and italics, there are a few other basic font changes you can use. Many linguisticky forumlae use small capitals, for which you can use \textsc. Note, though, that many fonts do not have a true small caps option. If you want to use proper ones, you'll need to pick your font carefully. You can use textsf to get a sans serif family, and \texttt for a "typewriter" family, with fixed character widths. In my own documentation, I find I mostly use italics and bold, with an occasional use of small caps, if I happen to be using a font that supports it. Unfortunately, Gentium, my favorite font, does not. Here are some fonts I know have small caps, apart from LaTeX's default Computer Modern (which I personally don't care for):

Your Style

In my conlang documentation, I like to use bold font for the conlang and italics for the English translations. So you might think that I have \textbf and \textit all over my documentation. I don't. Instead, I write macros which declare my intent ("this is the conlang," "this is the translation"). That way, if I were to one day change my mind, I only have to update a single macro instead of going through the entire text changing all the \textbfs to something else.

Fortunately, in LaTeX it is trivial to write my own versions of things like \textbf, and I do so freely. My personal convention is to put (English) translations into a \E macro and the example language in \LL. This is how they are defined —

\newcommand{\LL}[1]{\textbf{#1}}
\newcommand{\E}[1]{\textit{#1}}

So, what does all this mean. First, \newcommand does what you'd expect — it creates a new command. The next part, in curly braces, lets you name this new command of yours. Note that LaTeX is case sensitive, so \E and \e would be different commands. Also, note that if you accidentally try to use a name that is already defined somewhere in LaTeX, it will barf out and complain about the redefinition. This is why my "in the language" macro is \LL — there's already a \L in LaTeX (it gives a barred-L for languages like Polish).

The part in the square brackets says how many arguments the macro has. That is, how many different sets of curly braces there will be with the command. Finally is the body of the macro, which is what you want the macro to do. Within the body you can use #1 to refer to the first argument, #2 to the second, etc. So, my \LL macro has a single argument, which is wrapped up in the \textbf command.

On the surface, this looks sort of dumb. I have just written my own command to do something which LaTeX can already do. But, I've replaced a font styling command with a semantic command, for my personal cognitive benefit. \LL everywhere means "this is in the conlang" not just "this is in bold face." This gives me two advantages. First, I can go through the document looking just for examples of the conlang. Second, if I decided later I hate bold for the conlang, I can simply change the macro and let LaTeX do the rest.

You can also just put plain text within a new macro. For example, my dictionary stye has this:

\newcommand{\Seealso}[1]{See also \LL{#1}.}

Let's look at a command with more than one argument. This is a simplified version of my "Lexicon EXAMPLE" macro.

\newcommand{\lexample}[2]{\LL{#1} \E{#2}}

An example of us of this is, \lexample{tempus fugit}{time flies}. It will just print the Latin phrase in bold, a space, then the English translation in italics. Note very carefully — normal text parsing rules of LaTeX apply within a macro definition, so you need to take care about extra spaces or line ends. You can get weird effects, and I'll talk about ways to tame that in a later post.

For one last example, sometimes I make small notes to myself within the body of a document I'm working on. Because I want it to stand out, but not take up too much room, I format that note in a smaller font, but I use a different color.

\newcommand{\note}[1]{\textcolor{magenta}{\small\textit{#1}}}

If you're not using XeTeX, you'll probably need to \usepackage{color} to get this to work.

Etc.

A few weeks ago on the conlang-l mailing list someone mentioned that there's a nice LaTeX package to typeset vowel triangles in the way we're used to from a nice IPA chart. Ignoring other package and LaTeX setup details, you just need this: